% understanding about fftshift
clear
clc

w=linspace(0,10);
t=linspace(0,5);

a01=3;
a1=[1 a01];
b1=[a01];

h1=impulse(b1,a1,t);
H1=a01./(a01+j*w);

a02=1/3;
a2=[1 a02];
b2=[a02];

h2=impulse(b2,a2,t);
H2=a02./(a02+j*w);

figure(1)
clf
subplot(211)
plot(t,h1);
subplot(212)
plot(w,abs(H1));

figure(2)
clf
subplot(211)
plot(t,h2);
subplot(212)
plot(w,abs(H2));
